Modular, pre-tensioned, self-cleaning screening panels

ABSTRACT

A modular, pre-tensioned, self-cleaning screening panel having a frame and at least one pre-tensioned wire that is fastened to the frame.

FIELD OF THE INVENTION

This application is directed toward a screening panel used, for example,with a screening machine of the type used to separate or classifymixtures of solid particles of different particle sizes into classes ofdifferent sizes. In most instances, the screening panel is removablyattached to a vibratory screening machine.

BACKGROUND OF THE INVENTION

The screening machine can be used, for example, in the aggregateindustry or in mining industries. The aggregate and mining industriesutilize many types of machines to sort aggregates by size. Most suchmachines include a screening surface that includes a plurality of holesor openings. The machines utilize vibratory motions, defined below, toagitate a mixture of aggregates placed on the screening surface, topromote separation through the openings. Sorting is achieved byundersized particles passing through the openings in the screeningsurface and the oversize particles being retained above the screensurface. These machines usually have some type of vibrating mechanism toshake the unit and its screening surfaces. The vibrating mechanismsusually include an unbalanced weight mounted on one or several rotatingshafts which, when rotated, force a cycling motion into the screenmachine. The resulting motion can have a circular path, linear path,elliptical path, or any combination of those shapes. Another type ofconventional machine is a trommel or rotatory screening machine thatseparates materials using rotation. In these machines, round screens aredisposed in a rotating drum, with the material to be sorted by thescreens moving via the rotation of the drum.

Machines of the type just described can be configured to acceptdifferent types of screen media. One conventional type of screen is ahooked screen panel that includes a plurality of wires generallyparallel to each other. Opposite ends of the wires are provided withhooks or angled features. The hooks are coupled to a movable feature ona machine of the type described, and this movable feature is moved totension the wires at installation/replacement of the screen. Thetensioned wires then provide the screening surface. Of course,tensioning the screen panel of the type just described is atime-consuming and laborious process, usually requiring multipleinstallers.

Other types of vibratory machines of the type described above areconfigured to receive modular screens as screening media. As usedherein, “modular screens” generally refers to screens having a specificsize, shape, mounting features and/or configuration. Unlike the panelscreens described above, modular screens may have a fixed sized and/orshape, such that the screen material that sorts the aggregate is notand/or cannot be adjusted. Modular screens may have a fixed outer framethat is received in a receptacle of the vibratory machine. Some examplemodular screens may be over-molded with a polymer such as urethane orrubber to facilitate coupling of the screen to the machine and/or topromote movement of aggregate across the screening surface. The polymermaterial is used to attach the screen panel to the screen machine, andoften to also create the openings in the screen area. Modular screenstypically require only a single installer with minimal training andtime, and thus offer improvements over the screen panels discussedabove.

Some conventional modular screen panels use aligned, un-tensioned wiresto form the screening surface. In these examples, the wires are formedin a generally parallel arrangement, generally as in the screen panelsdiscussed above. However, because the modular frame has a fixed size,the wires in these conventional screens cannot be tensioned later. Theyare not tensioned at all. Because of this lack of tension, previousarrangements have been fabricated only using relatively larger diameteror gauge wire, because of the higher rigidity of these wires.Alternatively, or additionally, such screens have required additionalsupports to provide the rigidity lacking from the untensioned wires.However, these intermediate supports reduce throughput of the modularscreen.

Other conventional screen panels can include woven wire mesh as thescreening surface, instead of the generally parallel wires. Wire mesh,however, has well known drawbacks. For example, pieces of the aggregatebeing sorted by the mesh can become lodged in openings in the mesh.These lodged pieces reduce throughput of the machine, and clearing suchplugged pieces typically requires extra tools, for example a ball tray,and/or extra labor.

Thus, each of the conventional screen types described above hasdrawbacks. For example, the hook screen panel requires additional laborand expertise to install the screen on a vibratory machine. Modularscreens with wire screening arrangements use untensioned wires, whichlimits the functionality and/or types of screens that can be fabricated.Mesh screens are prone to clogging.

This disclosure provides improvements in screening media used withvibratory machines.

SUMMARY OF THE INVENTION

Screening panels are disclosed, along with machinery to manufacture thescreening panels and methods to manufacture the screening panel.

In one example, a screening panel includes a frame and a plurality ofwires. The frame includes a first frame end spaced from a second frameend in a longitudinal direction and a first frame side spaced from asecond frame side in a lateral direction. The wires extend from thefirst frame end to the second frame end. Individual of the plurality ofwires are coupled proximate a first wire end to the first frame end andare coupled proximate a second wired end to the second frame end. Theplurality of wires are in tension between the first wire end and thesecond wire end and are configured to vibrate independently of eachother.

An example method of manufacturing a screening panel includes providinga plurality of wires, the plurality of wires extending generally fromfirst wire ends to second wire ends in a longitudinal direction.Adjacent wires of the plurality of wires are arranged to provide aspacing therebetween. The method also includes providing a framecomprising a first frame end spaced from a second frame end in thelongitudinal direction and a first frame side spaced from a second frameside in a lateral direction. The method also includes at least one oftensioning the wires in the longitudinal direction or compressing theframe in the longitudinal direction, and with the at least one of theplurality of wires tensioned in the longitudinal direction or the framecompressed in the longitudinal direction, securing the first wire endsof the plurality of wires to the first frame end and securing the secondwire ends of the plurality of wires to the second frame end. The methodalso includes releasing the at least one of the tensioning or thecompressing with the wires secured to the frame to provide a screeningpanel with tensioned wires in which the wires are configured to vibrateindependently of each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1F illustrate various prior art wire configurations used inscreening panels.

FIG. 2 illustrates a frame.

FIG. 3 illustrates a cross-section of FIG. 2 taken along the lines 3-3.

FIG. 4 illustrates a frame with tensioned wires converted into ascreening panel.

FIG. 5 illustrates a dual carriage device having a frame carriagecompressing unit and a screen tensioning unit.

FIG. 6 illustrates an enlarged view of FIG. 3 taken along the line 6-6.

FIGS. 7A and 7B illustrate examples of cut wires from un-tensioned wires(FIG. 7A) and tensioned wires (FIG. 7B).

FIG. 8A illustrates how the adhesive encapsulates a wire in oneembodiment and FIG. 8B illustrates how the adhesive encapsulates a wirein another embodiment.

FIG. 9 illustrates a flow chart of manufacturing a screening panel.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated at FIG. 2, this application relates to a screening panel100 including a frame 110 and a plurality of wires 130 secured to theframe (see, FIG. 4) wherein the plurality of wires 130 contains at leastone pre-tensioned wire.

The frame 110 has a first attachment frame end 112, a second attachmentframe end 114 spaced in a longitudinal direction from the firstattachment frame end 112. The frame 110 also has a first frame side 116and a second frame side 118 spaced from the first frame side 116 in alateral direction. The first attachment frame end 112, the secondattachment frame end 114, the first frame side 116, and the second frameside 118 are connected to define the frame's outer perimeter 900 and theframe's inner perimeter 902. The frame's inner perimeter 902 defines ascreen spacing area 120. In examples, the wires 130 are positionedwithin the screen spacing area 120.

As also shown in FIG. 2, the wires 130 are secured at a first wire endto the first attachment frame end 112 and at a second wire end to thesecond attachment frame end 114. The wires are illustrated as aplurality of parallel wires extending in the longitudinal direction. Thewires are spaced from each other, e.g., from an adjacent wire, in thelateral direction by a predefined distance and/or in a predeterminedway. Together, the wires 130 define a plurality of openings sized and/orshaped to selectively permit material of a certain size (or smaller) topass therethrough.

In examples, the wires 130 may be arranged in a number of configurationsin which the opposite ends of the wires are fixed to the attachmentframe ends 112, 114. Examples of numerous wire configurations that canbe used for the wires 130 are shown in FIGS. 1A-1F. These configurationsinclude and are not limited to (1) a harp screen configuration, (2) aherringbone configuration (L-configuration), (3) a square configuration(M-configuration), (4) a double-square configuration (M-2configuration), (5) a triangle configuration (H configuration), and (6)a clean slot configuration.

The harp screen configuration, as illustrated at FIG. 1A, illustratesstraight wires wherein each wire 15 is essentially parallel with eachadjacent wire. The wires 130 in FIG. 2 are generally configured in theharp screen configuration.

The herringbone configuration, as illustrated at FIG. 1B, has aplurality of wires wherein each wire 6 (a) has the same zig-zag patternand (b) is essentially parallel with each adjacent wire.

The square configuration, as illustrated at FIG. 1C, has a plurality ofwires wherein (a) each wire has a zig-zag pattern having a plurality ofapex locations 10 and a plurality of nadir locations 12, and (b) eachwire's apex location 10 is positioned to contact or nearly contact asecond, adjacent wire's nadir location 12 and each first wire's nadirlocation 12 is positioned to contact or nearly contact an adjacentwire's apex location 10 to create a square or rectangular spacing 16between the adjacent wires.

The double square configuration, as illustrated at FIG. 1D, is avariation of the square configuration. Each wire set 144, 144′, 144″ istwo parallel or essentially parallel wires wherein each wire in the wireset has a zig-zag pattern having a plurality of apex locations 10 and aplurality of nadir locations 12. A second wire set's 144′ apex location10 is positioned to contact or nearly contact the third wire set's 144″nadir location 12 and the second wire set's 144′ nadir location 12 ispositioned to contact or nearly contact the first wire set's 144 apexlocation 10 to create a square or rectangular spacing 16 between theadjacent wire sets.

The triangle configuration, as illustrated at FIG. 1E, is a variation ofthe square configuration, with a straight wire 8 positioned betweenzig-zag wires 14.

The clean slot configuration, as illustrated at FIG. 1F, is analternative version of the harp configuration in that every straightwire 8 is adjacent to a crimped wire 9.

In examples of this disclosure, the wires 130 are arranged in the screenspacing area 120, e.g., in a configuration such as one of theconfigurations of FIGS. 1A-1F. As noted above, the wires 130 areattached at opposite ends to the attachment frame ends 112, 114 in thedesired configuration. Each of the wires 130 is spaced laterally fromadjacent wires. Unlike in a mesh, the wires 130 are not supported byinterwoven, laterally disposed wires.

The wires 130 may be arranged to have self-cleaning properties. Forexample, a self-cleaning screen has openings that can vary slightly insize or shape. For instance, in examples described herein, the wires130, or at least portions of the wires, are allowed to vibrateindependently, e.g., relative to each other, to slightly vary the sizeof the openings defined by adjacent wires. For instance, the wires 130of the present disclosure are fixed at their ends and are not otherwiseconstrained along their length. In other instances, motion of the wires130 may be minimally constrained between their ends, e.g., at a point ofcontacting the support member 150, at a point of contact with one ormore other support members, one or more laterally-extending wires, orthe like. Stated differently, the wires 130 or portions of the wires areallowed to vibrate to slightly vary openings between the wires 130. Byslightly increasing the size of an opening, a lodged or wedged materialmay become dislodged. In contrast, conventional non-self-cleaningscreens have openings that are generally fixed, e.g., by the nature of aweave, welding, molding or perforations in a sheet or plate.

The screening panel 100 can also have an interconnecting structure 352,made of conventional screening panel materials such as and not limitedto metallic material like steel, or a polymeric material like urethaneor rubber, or combinations thereof positioned over the frame 110 so theinterconnecting structure 352 is formed so the screening panel 100 canbe, preferably easily, removably attached to a specific screeningmachine (not shown). The interconnecting structure 352 can be any shapethat fits a specific screening machine. More specifically, the screeningpanel 100 has a generally fixed size and shape defined by the frame 110and/or the interconnecting structure 352. The size and shape aregenerally fixed or predefined to facilitate attachment of the panel to areceptacle or cooperating features of a vibratory machine. The term“modular” may be used herein to generally refer to such panels having afixed size, shape and/or arrangement of attachment features.

Collectively, the frame's interior perimeter—delineated by the firstattachment frame end 112, the second attachment frame end 114, the firstframe side 116, and the second frame side 118—defines the screen spacingarea 120. Likewise, the panel's interior perimeter—delineated by theinterconnecting structure 352 (a) over the frame 110; (b) under theframe 110; (c) on the frame's outer perimeter 900, (d) on the frame'sinterior perimeter 902, or (e) combinations thereof—defines the panelspacing 320. The screen spacing area 120 and the panel spacing 320 canbe the same size or different size especially if the interconnectingstructure is positioned on the interior perimeter 902.

Un-tensioned and tensioned are terms dependent on how a wire reacts whencut in (a) the screen spacing if the frame 110 is exposed or (b) thepanel spacing 320 if the interconnecting structure 352 is formed.

FIG. 7A illustrates tensioned wires 950, 952, and 954, as in examples ofour invention, interconnected to a frame (not shown) prior to cuttingthe wire (left side) and after cutting the wire (right side). Thetensioned wires 950, 952, and 954 were scored (or marked) in the samehorizontal plane 956. In the illustrated example, the horizontal plane956 provides a reference line extending laterally across the array ofwires. After marking the tensioned wires, Applicant cut wire 952 at 970.As illustrated, a reference line 962 on cut tensioned wire 952noticeably moved away (as shown in FIG. 7A the distance Y) from thehorizontal plane 956 while the uncut tensioned wires 950, 954 remain intheir original positions. With a tensioned wire, the measured distance Ybetween two marks on the wire decreases if the tension in the wire isremoved by cutting at a spot not between the two marks. It is understoodto those skilled in the art that a suitably accurate measurement betweentwo marks on a wire can be accomplished by various methods such as CMMor optical device with the two marks spaced significantly apart and thecentral axis of the wire aligned with a straight line. Further, it isunderstood that the decrease is relative to the wire's cross-sectionalarea. That means that a tensioned wire having a cross sectional area of,for example, 1 mm² will be significantly decreased compared to a wirehaving a cross-section area of, for example, 10 mm².

In contrast, FIG. 7B illustrates un-tensioned wires, including wires910, 912, and 914, as in some conventional arrangements, interconnectedto a frame (not shown) prior to the cutting the wire (left side) andafter cutting the wire (right side). The un-tensioned wires 910, 912,and 914 were scored (or marked) in the same horizontal plane 956). Afterscoring the un-tensioned wires, Applicant cut wire 912 at 930. Asillustrated, the score line 922 on cut un-tensioned wire 912 (alsoillustrated at line 926) and the score lines 920, 924 on uncutun-tensioned wires 910, 914 remained essentially in the same horizontalplane 936 and location as identified by the distance Z. With anun-tensioned wire, a measured distance between two marks on the wiredoes not materially change if the wire is cut at a spot not between thetwo score marks.

Stated differently, when a tensioned wire of the wires 130 is cut orbreaks, the tension in the wire causes the segments on either side ofthe cut to appreciably shorten or recoil. In contrast, untensionedwires, as in conventional arrangements, do not appreciably move.

The first attachment frame end 112 and the second attachment frame end114 can each have an upper bond area 122 and a lower bonding surface124, as illustrated at FIG. 3 and the magnified view of FIG. 6. (Notethat in FIG. 3, the wires 130 are omitted for clarity.) The upper bondarea 122 is positioned adjacent to the frame's interior perimeter 902while the lower bonding surface 124 is positioned adjacent to theframe's exterior surface 900. The upper bond area 122 and the lowerbonding surface 124 can be (a) two different pieces or (b) machined froma single piece. As illustrated at FIG. 6, the frame 100 has a base level800, a first level 802 that is equal to the height of the lower bondingsurface in relation to the base level, a second level 804 that is equalto the height of the upper bond area in relation to the base level, anda third level 806 that is equal to the height of the first frame side(and the second frame side) in relation to the base level. It isunderstood that the third level is above the second level, the secondlevel is above the first level and the first level is above the baselevel.

Although the frame 110 is illustrated as having a rectangular shape, theframe 110 is not limited to this shape. For example, the frame 110 maybe square, ovular, circular, have rounded features, or the like. Anyshape that allows for tensioning of the wires 130 as in examplesdescribed herein is contemplated.

The lower bonding surface 124 is configured to receive an adhesive 198that secures the wires 130 to the frame 110 while the first frame side116, and second frame side 118 are designed to have no adhesive thereonsince the first frame side 116, and second frame side 118 do notnormally secure any wire to the frame 110 or panel 100. Examples of theadhesive can be UV cured methyl methacrylate or acrylic ester, such asand not limited to Loctite's HH8003 or AA312 industrial adhesivematerial manufactured by the Henkel Corporation of Düsseldorf, Germany.Obviously, the adhesive could be altered to other adhesives like epoxymaterials. It is also understood that alternative methods such aswelding, sonic welding, screws, magnets, bending, nuts and bolts andcombinations thereof can also be used to secure the tensioned wires tothe frame. When the alternative method to secure the tensioned wires tothe frame is used, it is preferable to weld the tensioned wires to theframe on the upper bond area 122, the lower bonding surface 124 andcombinations thereof. In some examples, the upper bond area 122 is notnecessary.

In any case, when an adhesive material is used, the upper bond area 122inhibits the adhesive material from leaking into the screen spacing 120and ensures the wires 130 remain in or near (in many instances, slightlyabove as a result of size constraints) a neutral axis of bending 132(defined below) with the frame 110. The upper bond area 122 alsoprovides the adhesive support against shear forces on the firstattachment frame end's 112 and the second attachment frame end's 114 topsurface 940 (illustrated at FIG. 6) and requires the adhesive 198 failsin tension upward before shear becomes an issue.

As previously expressed, the frame 110 has the first attachment frameend 112, the second attachment frame end 114, the first frame side 116,and the second frame side 118. Likewise, it is possible that the frame110 can have one or more additional support members to enhance therigidity of the frame 110 and/or to further support the wires 130. Forexample, and as illustrated at FIGS. 2 and 3, the frame 110 can includea support bar 150 extending laterally, e.g., generally parallel to thefirst attachment frame end 114 and the second attachment frame end 114.Although a single support bar 150 is illustrated, more than one supportbar 150 may be provided. Moreover, in some instances the support bar 150may not be required. Reducing the number of support bars 150 may bebeneficial, e.g., because each support bar reduces the effectivescreening area of the screening panel. The support bar 150 may providesupport to (a) the frame 110 when the frame 110 is compressed(illustrated by arrow 200) during the manufacturing process of thescreening panel 100 or (b) the screening panel when the screening panel100 experiences vibration forces by the screening machine. Inparticular, each support bar 150 extends from the first frame side 116to the second frame side 118 to inhibit the frame 110 or screening panel100 from bending (illustrated by arrow 202) or bowing too much when theframe 110 is being compressed during the manufacturing of the screeningpanel 100 or the screening panel is vibrated by a screening machine.

The support bar 150 is one example of a support member that enhances therigidity of the frame 110. In other examples, the frame 110 can includeother support members, including but not limited to one or morelongitudinally extending support members, e.g., positioned between andparallel to the first frame side 116 and the second frame side 118.Other support members can include angled or oblique support members. Asnoted above, the frame 110 may include no additional support member.

When a support member, like the support bar 150, is provided in thescreening area, the wires 130 may contact the support member. In someexamples, the wires 130 may be fixed or attached to the support member,using welding, adhesive, or the like. Even when attached to the supportmember, the wires 130 are able to vibrate to provide the self-cleaningproperties discussed above. For instance, a sufficient amount of thewires 130 extends between the support bar 150 and the frame ends 112,114 that is capable of independent vibration.

The first frame side 116 and the second frame side 118 each have aneutral axis. The neutral axes of each the first and second frame sidesare normally positioned at the halfway point of the height of therespective first and second frame side. The present invention directsthe forces in the wires in the plane between the neutral axis of thefirst frame side 116 and the neutral axis of the second frame side 118to decrease and inhibit bending the frame 100. The plane positionedbetween the neutral axis of the first frame side 116 and the neutralaxis of the second frame side 118 are referred to as the neutral axis ofbending 132. It is preferred, the wires 130 are designed to bepositioned therein or near the neutral axis of bending 132. The neutralaxis of bending 132 is designed to be the location in which all forcesapplied to the screening panel 100 (and frame 110) are supposed to beconcentrated in order to minimize the bending of the screening panel 100(and frame 110).

Tensioned wires are positioned in or near the neutral axis of bending132 to decrease and/or inhibit the wires from bending up (arrow 202) ordown—depending on the tension—in the frame 110. Likewise, the tensionedwires are in the neutral axis of bending 132 to inhibit the frame frombending up (arrow 202) or down—depending on the tension.

As previously addressed, this invention is directed to modular screenswith tensioned wires. As detailed further herein, screens of thisdisclosure can be manufactured by tensioning wires and/or compressing aframe prior to fastening the wires to the frame. Applicants haveconfirmed through experimentation that if tensioned wires that areevenly tensioned or about evenly tensioned are applied to anon-compressed frame, then the resulting screening panel has wirespositioned near the first and second frame sides retaining the desiredtension while the remaining middle section wires lose tension as aresult of the frame deflecting as a result of the tensioned wires. Thelost tension of the middle section wires is significant because themiddle section then does not function as an effective self-cleaningscreen.

Another advantage of the present invention is that tensioned wiresapplied to a compressed frame permits the screen spacing 120 to bemaximized by minimizing the number of support bar(s) 150 and/or othersupport members, which may include supports that extend between thefirst frame end and the second frame, for instance, parallel to thefirst and second frame sides, except positioned in the screen spacingarea 120. Additional support members have been utilized in prior artscreen frames of the same size. That being said, the support bar 150and/or additional support member may be used in some screen frameembodiments of the present invention.

To further assist in minimizing the bending of the screening panel 100,the support bar 150 (and/or other support members) may be positionedproximate the neutral axis 132. With this arrangement, the support bar150 assists in directing any forces applied to the screening panel 100into the neutral axis 132. For instance, the support bar 150 may resistlateral displacement of the sides 116, 118 away from each other when theframe 110 is under compression. In other examples, the support bar 150may be slightly above or below the neutral axis 132, such that the wires130 can be disposed in the neutral axis 132. In examples, the number ofsupport bars 150 and/or other support members may be minimized, toreduce an impact on throughput of the screening panel 100, as notedabove. Fewer support bars results in the screening panel 100 being abetter self-cleaning device with greater throughput since the presentinvention's use of pre-tensioned wires minimizes the spacing between thewires from expanding such that the screens have an increased efficiencyof self-cleaning properties.

When the tensioned wires 130 (the tension force is illustrated by arrows204 and range from 2,000 to 5,000 lbs.) are positioned in or as close tothe neutral axis 132 as possible, then the tensioned wire 130 can beattached to the frame 110 when the frame 110 is being or alreadycompressed (the compression force is illustrated by arrows 200 and rangefrom 1,000 lbs. to 3,000 lbs.) during the manufacturing process. Thescreening panel 100 experiences (a) compression forces on the frame 110and (b) the tension forces when the tensioned wires are securelyattached to the frame 110 at or near the same time, then the screeningpanel 100 should experience lower bending forces (arrows 202). That inturn, should render the screening panel 100 a more stable product thatretains the desired wire tension that results in superior self-cleaningcharacteristics and greater throughput capabilities.

As can be readily appreciated, the wires 130 are tensioned in onedirection (see arrows 204) when positioned and attached to theframe—between the first attachment frame end 112 and the secondattachment frame end 114—and in the neutral axis 132. It is alsounderstood that the wires 130 can have different tensions. For example,the wires 130 positioned or to be positioned at or near the center of(A) the screen spacing area 120 and (B) the first attachment frame end112, the second attachment frame end 114 can be at a higher tension (1to 50% greater, 5 to 25% greater and/or 10 to 20% greater) than thewires 130 positioned or to be positioned at or near the first frame side116 and the second frame side 118 and/or any support member parallel tothe frame sides. That various tensioned wire embodiment, combined withthe optional compressed frame 110, provides for more consistenttensioning of all wires in the screening area. For example, along theattachment frame ends 112, 114, the frame is more rigid proximate thesides 116, 118, than at positions nearer the centers of frame ends 112,114 (spaced from the sides 116, 118). Because of this varied rigidity,the frame may provide different resistances to the tensioned wires, andin this example the wires are tensioned based on these differentresistances, with the result being more evenly tensioned wires.Differently tensioning the wires may result in a more efficientself-cleaning screen apparatus.

It is also understood that some of the wires 130 positioned adjacent toor very near the first frame side 116 and/or the second frame side 118could be un-tensioned while the remaining wires 130 positioned along andnear the screen spacing area's 120 center line 125 that extends from thefirst attachment frame end 112 to the second attachment frame end aretensioned. The more efficient self-cleaning screen apparatus ismaintained with the present invention on the condition that theun-tensioned wires 130 positioned adjacent to or very near the firstframe side 116 and/or the second frame side 118 have a tension strengthafter the frame is decompressed that is the same or equivalent (within 1to 25%) of the tension of the tensioned wires 130 positioned along andnear the screen spacing area's 120 center line 125, when the frame isdecompressed.

That one directional wire tensioning also permits the wires 130 while inthe screening panel 100 to provide (i) a more efficient self-cleaningscreen apparatus and (ii) greater precision in the throughput when thescreening panel 100 is installed in the screening machine. Moreover,when the screening panel 100 is installed in the screening machine, thescreening panel 100 with the tensioned wires 130 is not subject tofurther tensioning of the frame 110 and/or wires 130 since the screeningpanel 100 with the tensioned wires 130 is properly sized to easily beinstalled into the screening machine without applying further tension tothe screening panel 100 when being installed. It is understood that thescreening panel 100 may be further tensioned in some screening machinesduring installation or operation, however that is unlikely since thepresent invention's modular, self-cleaning screens is designed to beplaced in a receptable for vibratory screening machine. But for the mostpart, the screening panel 100 need not be further tensioned with mostvibratory screening machines.

In contrast, when un-tensioned screening panels are installed intoscreening machines, the un-tensioned screening panels must be adjusted,in many instances by numerous employees, into the screening machine toproperly be installed therein and obtain the desired tension in thewires and frame. Such endeavors are undesirable, and objectives can bedifficult or unpredictable to achieve.

Making one version of the tensioned screening panel is accomplished by amulti-step process using a dual carriage device 300. The dual carriagedevice 300 has a frame compressing unit 310 and a screen tensioning unit330, as illustrated at FIG. 5.

The frame compressing unit 310 has a first securing unit 312 thatreleasably secures the first attachment frame end 112 in the properposition during the assembly process of the screening panel 100; and asecond securing unit 314 that releasably secures the second attachmentframe end 114 in the proper position during the assembly process of thescreening panel 100. The first securing unit 312 and the second securingunit 314 can releasably secure the respective first and secondattachment frame ends 112, 114 through clamps, screws, nuts and bolts,or combinations thereof; or alternatively the first securing unit 312and the second securing unit 314 merely contact and push the respectivefirst and second attachment frame ends 112, 114 toward each other.

In one embodiment illustrated at FIG. 5, the second securing unit 314 isstationary while the first securing unit 312 is on a carriage 313. Thecarriage 313 moves on rails 319 in directions—identified by arrows318—parallel to the first frame side and the second frame side when theframe 110 is releasably secured (or contacted and pushed) in the firstand second securing units 312, 314. The first securing unit 312 on thecarriage 313 and interconnected to a hydraulic system (or servo-motors,linear actuators or other types of actuators) 316 moves toward the lowersecuring unit 314 and can compress (arrows 200) the frame 110 apredetermined distance. The hydraulic system 316 can be hydraulic fluidcontained in conventional pistons in order to control the movement ofthe upper securing unit 312; or alternatively, the hydraulic system 316could be replaced with any other system that accomplishes the sameobjectives as the hydraulic system 316. For example, the relativemovement could be accomplished using a manually-operated system, asystem driven by servo motors, linear actuators, pneumatics, or thelike. The upper securing unit 312 in conjunction with the hydraulicsystem 316—after an operator (a) positions the frame 110 within theupper securing unit 312 and the lower securing unit 314 and (b)initiates the hydraulic system 316—compresses the first attachment frameend 112 toward the second attachment frame end 114 a predetermineddistance. The predetermined distance can range from 0.01 mm to 2 mm. Inthe alternative way, at least one block contacts the attachment frameend 112 and at least one pusher contacts the second attachment frame end114 (or vice versa or there are at least one pusher on each frame end112, 114). The at least one pusher moves and causes each frame end 112,114 to bow under the compressive force resulting from the movement. Atwhich point, the pre-tensioned wires are attached to the bowed frame andthe bowing resists the tension. The displacement of the frame ends 112,114 will vary across the width as a result of the bowing, with theunderstanding that in the middle of the frame ends 112, 114 the distancewill be greater and at the sides of the frame ends 112, 114 the distancewill be less.

Alternatively, the lower securing unit 314 can be on the carriage 313and interconnected to the hydraulic system 316, and the upper securingunit 312 is stationary. The hydraulic system 316 can be hydraulic fluidcontained in conventional pistons in order to control the movement ofthe lower securing unit 314; or alternatively, the hydraulic systemcould be replaced with any other system that accomplishes the sameobjectives as the hydraulic system 316. For example, the relativemovement could be accomplished using a manually-operated system, asystem driven by servo motors, linear actuators, pneumatics, or thelike. The lower securing unit 314 in conjunction with the hydraulicsystem 316—after an operator (a) positions the frame 110 within theupper securing unit 312 and the lower securing unit 314 and (b)initiates the hydraulic system 316—compresses the second attachmentframe end 114 toward the first attachment frame end 112 a predetermineddistance.

Alternatively, the lower securing unit 314 and the upper securing unit312 are respectively on their own carriages 313 and interconnected tothe hydraulic system 316. The hydraulic system 316 can be hydraulicfluid contained in conventional pistons in order to control the movementof the upper and lower securing units 312, 314; or alternatively, thehydraulic system 316 could be replaced with any other system thataccomplishes the same objectives as the hydraulic system 316. Forexample, the relative movement could be accomplished using amanually-operated system, a system driven by servo motors, linearactuators, pneumatics, or the like. The upper and lower securing units312, 314 in conjunction with the hydraulic system 316—after an operator(a) positions the frame 110 within the upper securing unit 312 and thelower securing unit 314 and (b) initiates the hydraulic system316—compresses the second attachment frame end 114 and the firstattachment frame end 112 toward each other a predetermined distance.

Either prior to or after the frame 110 is compressed, the operatorapplies the adhesive 198 on the lower bonding surface 124. The adhesive198 is sufficiently applied so that when the wire 130 is properlypositioned on the frame 110, the portion of the wire 130 that issupposed to contact the adhesive 198 is also encapsulated by theadhesive 198 as illustrated at FIGS. 8A and 8B. By encapsulated, thewire's top surface, bottom surface and both side surfaces are in theadhesive 198. That way, there is no bond area starvation below, above oron the sides of the portion of the wire 130 that is supposed to contactthe adhesive 198. The wire 130 can (a) have a slight bend as it ispositioned over the upper bond area 122, and the lower bonding surface124 as illustrated at FIG. 8A or (b) conform to the shape of the upperbond area 122 and the lower bonding surface 124 as illustrated at FIG.8B.

Either prior to or after the frame 110 is compressed, the wires130—having any of the above-identified configurations or combinationsthereof—are releasably secured to the screen tensioning unit 330. Likethe frame carriage compressing unit 310, the screen tensioning unit 330has a first tensioning unit 332 that releasably secures a first locationof the wires 130 in a proper position during the assembly process of thescreening panel 100; and a second tensioning unit 334 that releasablysecures a second location of the wires (usually the first location isone end of the wire to be tensioned and the second location is theopposite end of the wire to be tensioned) in the proper position duringthe assembly process of the screening panel 100.

In one embodiment, the upper tensioning unit 332 is stationary while thelower tensioning unit 334 is on a carriage system 335. The carriage 335moves on rails 339 in directions—identified by arrows 338—parallel to(a) the first frame side and the second frame side when the frame 110 isreleasably secured in the first and second securing units 312, 314, and(b) the wires 130 when the wires 130 are releasably secured in the firstand second tensioning units 332, 334. The second tensioning unit 334 onthe carriage 335 and interconnected to a second hydraulic system 336moves away from the first tensioning unit 334 and to provide tension(arrows 204) to the wires 130 by moving a predetermined distance.

The second hydraulic system 336 (i) operates in the same way ashydraulic system 316 and (ii) could be the same system as the hydraulicsystem 316. After (a) the wires are properly positioned in the first andsecond tensioning units 332, 334; (b) the wires need to be tensioned,and (c) the operator initiates the second hydraulic system 336—thesecond tensioning unit 334 moves away from the first tensioning unit 332a predetermined distance to obtain the desired tension for the screeningpanel 100.

Alternatively, the second tensioning unit 334 is stationary while thefirst tensioning unit 332 is on a carriage system—interconnected to asecond hydraulic system 336—that moves—after (a) the wires are properlypositioned in the first and second tensioning units 332, 334; (b) thewires need to be tensioned, and (c) the operator initiates the secondhydraulic system 336—the first tensioning unit 332 away from the secondtensioning unit 334 a predetermined distance to obtain the desiredtension for the screening panel 100.

Alternatively, the first tensioning unit 332 is on an first carriagesystem and the second tensioning unit 334 is on a second carriagesystem, wherein the first carriage system and the second carriage systemare interconnected to the second hydraulic system 336 that moves—after(a) the wires are properly positioned in the first and second tensioningunits 332, 334; (b) the wires need to be tensioned, and (c) the operatorinitiates the second hydraulic system 336—the second tensioning unit 334and the first tensioning unit 332 away from each other a predetermineddistance to obtain the desired tension for the screening panel 100.

Once (a) the wires 130 are tensioned, (b) the frame 110 is compressed,and (c) the adhesive 198 is applied to the frame 110, the frame carriagecompressing unit 310 is moved (see, arrows 360) toward the screentensioning unit 330 so the frame 110 and the adhesive 198 contacts thewires 130 located between the second tensioning unit 334 and the firsttensioning unit 332. The wires are then securely attached after theadhesive is cured to the frame 110 and the wires. That movement 360 canbe accomplished by conventional hydraulic motions using, for example,the hydraulic system 316.

Alternatively, when the frame 110 is compressed and the tensioned wires130 contact the second attachment frame end 114 and the first attachmentframe end 112, an operator can weld the tensioned wires 130 that contactthe frame 110 to the second attachment frame end 114 and the firstattachment frame end 112.

Once the tensioned wires 130 are fastened or secured to the optionallycompressed frame 110, the screen tensioning unit 330 is adjusted so ifthere are portions of the wires not positioned in the screen spacing 120and attached to the frame 110 become un-tensioned. The un-tensionedwires can then be safely cut or removed so the compressed frame 110 andtension wires 130 can be removed from the dual carriage device 300.

In the example just described, the wires are put in tension and theframe is compressed prior to wires being fixed to the frame. Forces inthe compressed frame counter forces in the tensioned wires to maintainthe wires in tension when the connected wires and frame are removed fromthe dual carriage device. Although the example just discussed achievesthis tension through both the tensioning of the wires with the screentensioning unit and the compression of the frame using the framecompressing unit, other example methods may include only tensioningwires with the screen tensioning unit. In some examples, the frame mayhave sufficient rigidity to resist the tension of the wires without theneed to first compress the frame. In another example, untensioned wiresmay be secured to a frame maintained in compression, for example, by theframe compression unit. When the compression is released, the frame mayapply a force to wires sufficient to place the wires in tension.

Other variations to the described method also may be used. For example,although the screen tensioning unit is illustrated as clamping all wiresand tensioning them uniformly, in other examples the screen tensioningunit can tension wires independently or in groups, similar to theexample discussed above. For example, wires closer to the frame sidesmay require less tension (because the sides provide additional framerigidity) whereas wires closer to the center of the attachment frameends may be subjected to a higher tension (because they are farther fromthe sides and therefore the frame has less rigidity). In addition to thebenefits discussed above, this selective tensioning may be particularlyuseful in methods that do not include pre-compression of frame, becausethe frame will resist the tensioning differently at different area.Other methods and/or modifications also are contemplated.

Regardless of the method used, we have demonstrated a modular screeningpanel having a fixed size and/or shape with tensioned wires. The use ofwires allows for the screen to be self-cleaning, thereby providingimprovements over mesh screens. Moreover, by tensioning the wires atmanufacture or fabrication, screens disclosed herein provideimprovements over panel screens that require tensioning at installation.Furthermore, tensioning the wires at manufacture provides an improvedscreen over modular screens that do not have tensioned wires. Withoutlimit, because previous modular screens did not have tensioned wires,they were usually fabricated from wires having some minimal rigidity(generally thicker wires) to prevent sagging or excessive movementduring vibration. Alternatively, previous modular screens withouttensioned wires needed several supports for the wires, to prevent thissagging and excessive movement, which reduced overall throughput of thescreen.

It may be possible to add one or more additional wires to the wires 130in the screen spacing area 120. For instance, these additional wires maynot be parallel with the tensioned wires 130. The wires may be used forsupport, e.g. as with the support member 150, or for other purposes. Thedisclosure is not limited to only wires, like the wires 130, extendinggenerally in a single direction. However, examples of this disclosuremay differentiate over mesh patterns that require interwoven wires indifferent directions that may prohibit the self-cleaning of the screen,as described herein.

FIG. 9 is an examples flow chart showing an example process 900 formanufacturing a screen panel, such as the panel 100.

At an operation 980, the process 900 includes tensioning a plurality ofwires and/or compressing a frame. These operations are detailed above.For example, tensioning the plurality of wires may include gripping,clamping or otherwise securing the wires proximate a first end by afirst unit and proximate an opposite, second end by a second unit, andmoving the units relative to each other, e.g., away from each other, toplace the wires in tension. Compressing the frame may include placingthe ends of a frame between movable units and moving the units relativeto each other, e.g., closer to each other, to compress the frame. Forinstance, the compression may cause portions of the ends of the frame tobow or displace so as to be relatively closer to each other.

At an operation 982, the process 900 includes securing the wires to theframe. As discussed above, with the wires in tension and/or the frame incompression, the wires are welded, adhered or otherwise secured to theframe ends.

At an operation 984, the process 900 includes releasing the tensionand/or compression. In some examples, a machine, such as the dualcarriage machine discussed above may be used to place the wires intension and/or the frame in compression. Upon securing the wires to theframe, e.g., after a curing time for adhesive, cooling of welds or thelike, the machine may remove the tension and/or compression. Oncereleased, the frame and the wires reach an equilibrium in which thewires remain (or are placed) in tension and the frame remains (or isplaced in) compression. The result is a screening panel 120 withtensioned wires, as in FIG. 2.

In some examples, the process 900 may include additional steps. Forinstance, the process 900 can include additional steps to modify thepanel 120 for use in different machines.

At an operation 986, the process 900 can optionally include masking thewires. For example, a mask may be applied to the tensioned wires 130that are to be exposed when the screening panel is in use. For instance,the portions of the tensioned wires 130 that are arranged in the panelspacing 320 may be masked.

At an operation 988, the process 900 can also optionally includeapplying additional structure to the unmasked areas of the screen 320.For instance, the additional structure may comprise the interconnectingexterior structure 352. In some examples, the additional structure canbe a polymeric structure, such as urethane, rubber, or the like. Theadditional structure may be designed so the screening panel 100 can beremovably and securely positioned in a desired vibratory machine.

The operation 988 may include applying the additional structure using amolding process, such as molding or injection molding. In some examples,a die or mold includes a cavity sized to receive portions of thescreening panel 120 with tensioned wires. For instance, the die or moldcan include a cavity that receives the frame 110 and provides additionalspacing around the frame 110. Mold material, e.g., liquid polymer, isintroduced into the cavity. Upon curing, the mold material encapsulatesthe frame 110, e.g., on all sides, as well as the attachment of thewires 130 to the frame 110. When the die is removed, the result may bethe modular screen 100 with interconnecting structure 352, shown in FIG.4. As also illustrated in FIG. 4, the mold material can also encapsulatethe support bar 150 and portions of the wires 130 proximate the supportbar 150. While not shown specifically in FIG. 4, the mold material mayfurther contact (and/or encapsulate) additional portions of the wires130. Without limitation, portions of the wires 130 closest to the sides112, 114 may be at least partially encapsulated by the mold material.

In at least some examples, the mold or die used to create the panel 100of FIG. 4 may be sized to receive the entire frame 110. For example, theframe 110 with tensioned wires 130 may be placed in a die that includescavities to create all of the exterior interconnecting structure 352,e.g., in a single mold step. In some examples, the mold or die mayinclude a masking region that receives portions of the wires 130 thatare not to be overmolded. Without limitation, the masking region caninclude a soft polymer that is configured to receive and contactportions of the wires 130 in one or more of the configurations discussedabove. Applying the exterior structure 352 in a single step moldprocessing obviates the need for one or more additional fabricationsteps. For instance, some conventional modular screens mold their framesprior to attachment of their untensioned wires. In some instances, endsof these untensioned wires may also be molded. The wires are thenfastened to the screens.

Although the operation 988 is described in connection with applying apolymeric or molded material as the additional structure, otheradditional structures are contemplated. The additional structures mayvary based on the vibratory machine with which the modular screen 100 isto be used. For instance, the additional structure can include mountingstructures such as flanges, tabs, detents, fasteners, or the like. Inother examples, this additional structure may be initially included inthe frame 110. The additional structure can also include gaskets,spacers, seals and/or the like. As noted, the additional materials maybe added to facilitate use of our screen with tensioned wires withdifferent types of vibratory machines. As will be appreciated, with theoperation 986 does not require applying a mold as the additionalstructure, the process 900 may omit masking the wires at the operation986.

Thus, it is seen that the objects of the present invention areefficiently obtained, although modifications and changes to theinvention should be readily apparent to those having ordinary skill inthe art, which modifications are intended to be within the spirit andscope of the invention as claimed. It also is understood that theforegoing description is illustrative of the present invention andshould not be considered as limiting. Therefore, other embodiments ofthe present invention are possible without departing from the spirit andscope of the present invention.

The invention claimed is:
 1. A screening panel comprising: a framecomprising a first frame end spaced from a second frame end in alongitudinal direction and a first frame side spaced from a second frameside in a lateral direction; and a plurality of wires pre-tensioned andfixed to the frame, the plurality of wires extending from the firstframe end to the second frame end, individual of the plurality of wiresbeing fixed proximate a first wire end to the first frame end and beingfixed proximate a second wire end to the second frame end, the pluralityof wires being pre-tensioned between the first wire end and the secondwire end and being configured to vibrate independently of each other. 2.The screening panel of claim 1, wherein the wires are in tension suchthat, when a wire of the plurality of wires cut at a longitudinalposition between the first wire end and the second wire end, at leastone of a first portion of the wire between the first wire end and thecut shortens in the longitudinal direction or a second portion of thewire between the second wire end and the cut shortens in thelongitudinal direction.
 3. The screening panel of claim 1, wherein atleast one of the first frame end or the second frame end furthercomprises a bonding surface and a raised bonding surface.
 4. Thescreening panel of claim 3, wherein the plurality of wires contact theraised bonding surface and are secured to the bonding surface using anadhesive, the raised bonding surface inhibiting migration of theadhesive prior to curing.
 5. The screening panel of claim 1, wherein theplurality of wires are pre-tensioned from about 2,000 lbs. to about 5000lbs.
 6. The screening panel of claim 1, further comprising a polymericstructure encapsulating at least a portion of the frame and ends of theplurality of wires, the polymeric structure having at least one of asize or a shape to facilitate coupling of the screening panel to avibratory machine.
 7. The screening panel of claim 6, wherein thepolymeric structure at least partially encapsulates at least one of afirst wire of the plurality of wires proximate the first frame side or asecond wire of the plurality of wires proximate the second frame side.8. The screening panel of claim 1, wherein: the frame further comprisesat least one support extending laterally between the first frame sideand the second frame side, at a position spaced from the first frame endand the second frame end; and the plurality of wires are disposed tocontact the support.
 9. The screening panel of claim 1, wherein: thefirst frame end has a first neutral axis extending generally along alongitudinal axis of the first frame end; the second frame end has asecond neutral axis extending generally along a longitudinal axis of thesecond frame end; and the plurality of wires are arranged proximate aplane coincident with the first neutral axis and the second neutralaxis.
 10. A method of forming a screening panel comprising: providing aplurality of wires, the plurality of wires extending generally fromfirst wire ends to second wire ends in a longitudinal direction andadjacent wires of the plurality of wires being arranged to provide aspacing there between; providing a frame comprising a first frame endspaced from a second frame end in the longitudinal direction and a firstframe side spaced from a second frame side in a lateral direction; withthe plurality of wires separate from the frame, at least one oftensioning the wires in the longitudinal direction or compressing theframe in the longitudinal direction; with the at least one of theplurality of wires tensioned in the longitudinal direction or the framecompressed in the longitudinal direction, securing the first wire endsof the plurality of wires to the first frame end and securing the secondwire ends of the plurality of wires to the second frame end; andreleasing the at least one of the tensioning or the compressing with thewires secured to the frame to provide a screening panel withpre-tensioned wires in which the wires are configured to vibrateindependently of each other.
 11. The method of claim 10, wherein the atleast one of the tensioning the un-tensioned wires or the compressingthe frame comprises tensioning the un-tensioned wires, the tensioningthe un-tensioned wires comprising: securing, via a first unit, theplurality of wires proximate the first wire ends; securing, via a secondunit, the plurality of wires proximate the second wire ends; and movingthe first unit relative to the second unit to place the plurality ofwires in tension.
 12. The method of claim 11, wherein the moving thefirst unit relative to the second unit imparts a force of from about2000 pounds to about 5000 pounds of tension on the plurality of wires.13. The method of claim 10, wherein the at least one of the tensioningthe un-tensioned wires or the compressing the frame comprises tensioningthe un-tensioned wires, the tensioning the un-tensioned wirescomprising: tensioning a first wire of the plurality of wires to a firsttension; and tensioning a second wire of the plurality of wires to asecond tension.
 14. The method of claim 10, wherein the at least one ofthe tensioning the un-tensioned wires or the compressing the framecomprises compressing the frame, the compressing the frame comprising:contacting a first unit to the first frame end; contacting a second unitto the second frame end; and moving the first unit relative to thesecond unit to move at least a portion of the first frame end relativelycloser to the second frame end.
 15. The method of claim 10, wherein atleast one of the securing the first wire ends to the first frame end orthe securing the second wire ends to the second frame end comprises atleast one of adhering or welding.
 16. The method of claim 10, furthercomprising: applying an overmold to the screening panel with tensionedwires.
 17. The method of claim 16, wherein the overmold encapsulates atleast a portion of the first frame end, the second frame end, the firstframe side, the second frame side, the first wire ends and the secondwire ends.
 18. The method of claim 16, wherein the overmold furtherencapsulates at least a portion of the at least one of a first wire ofthe plurality of wires proximate the first frame side or a second wireof the plurality of wires proximate the second frame side.
 19. Ascreening panel for use in a vibratory machine comprising: a frameincluding frame ends and frame sides; a plurality of pre-tensioned wiresextending between and fixed to the frame ends, the pre-tensioned wiresbeing arranged to define spaces through which material can pass duringuse of the vibratory machine, and individual of the pre-tensioned wiresbeing fixed to the frame ends independently of other of the plurality ofpre-tensioned wires; and an interconnecting structure disposed over theframe and at least a portion of the plurality of pre-tensioned wires,the interconnecting structure providing the screening panel with a fixedsize and shape for coupling to the vibratory machine.
 20. The screeningpanel of claim 19, wherein the interconnecting structure comprises amolded polymer.